Thanks for your answer. Although not the explicit answer to my question it certainly brought me on the right track.
As noted by mti2935 this was indeed not a perl problem, but a mere tty configuration problem.
Using the "stty" command with the following parameters set my serial port in the "expected" mode:
- -opost: Disable all output postprocessing
- -crnl: Do not translate CR to NL
- -onlcr: Do not translate NL to CR NL
- -echo: Do not echo input (having this echo enabled and echo on the modem itself gave me double echoes resulting in odd behaviour in my script)
It is also possible to use the combination setting "raw" to set all these parameters the correct way.
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